1. Field of the Invention
The present invention relates to apparatus for uniformly buffing and removing unwanted particles from the surface of a photoconductor, so that the photoconductor may be restored to a condition suitable for immediate re-use in an electrographic apparatus.
2. Description of the Prior Art
Images are formed in an electrographic apparatus by moving a photoconductor, in the form of a drum or flexible web, past a series of stations in the apparatus. As this occurs, the photoconductor is charged, exposed to form a latent charged image on the photoconductor, and the image is then developed by moving it past a development station where charged toner particles of developer material are attracted to the charged latent image to develop the image. The developed image is then transferred to a receiver sheet, such as a sheet of paper, at a transfer station. The receiver sheet, carrying the developed image, is advanced through a fusing station where the toner particles are heated and fused to the sheet. Particles remaining on the photoconductor, after transfer to the copy sheet has occurred, are removed at a cleaning station prior to recharging the photoconductor and repeating the copy process.
During the above processes of charging, developing, transfer and cleaning, each subsystem of the process interacts with the others. However, most interaction takes place between immediate neighboring systems. In the case of the cleaning subsystem, the effects of transfer and charging have the most effect on cleaning. The toner that remains behind on the photoconductor, after transfer, has to be cleaned off the photoconductor before the charger can uniformly charge the web, since the charging system is designed to charge a cleaned photoconductive surface. If the surface is not uniformly cleaned, the desired levels of charge needed on the photoconductor will not be achieved.
Since the photoconductor is used over and over again for thousands or perhaps hundreds of thousands of images, its surface must be continuously restored. Therefore, the photoconductor must be buffed, as well as cleaned, at a controlled and uniform rate. The required buffing rate is dependent upon the application. Sometimes it is necessary to buff the photoconductor very aggressively. A magnetic brush cleaner system is one of the typical systems used with electrophotographic copiers, printers and the like, to remove residual toner and buff the surface of the photoconductor after transfer. One type of magnetic brush cleaning system that is used has a very dense nap of coarse magnetic particles, but unfortunately, this type of nap has little compliancy. To overcome this compliancy problem when using a photoconductor belt in the form of a loop, one usually attempts to obtain the necessary compliancy by optimizing the loop support system in the vicinity of the cleaning apparatus in hopes of maintaining buffing uniformity over the width of the photoconductive web.
At the present time, one loop system that accomplishes the above consists of two stationary skis that straddle the cleaning brush where the deflection of the photoconductive belt occurs, between the two skis, to provide sufficient compliancy for cleaning. A problem with this technique is the lack of electrical uniformity along the photoconductor after normal cleaning due to uneven buffing which results in uneven wear and non-uniform electrical response of the photoconductor.